What Is Rotational Molding?

Rotational molding, also known as rotomolding, rotary molding, etc., is a hollow molding method for thermoplastics. The method is to add plastic raw materials first into the mold, and then the mold is continuously rotated along two vertical axes and heated. Under the action of gravity and thermal energy, the plastic raw materials in the mold are gradually uniformly coated and melted and adhered to the mold cavity. The whole surface is formed into the required shape, and then cooled and shaped into a product.

The basic process of rotational molding is very simple. It is to put powdered or liquid polymer in a mold, heat it, and the mold rotates and revolves around a vertical axis, and then cools to form. At the beginning of the heating stage, if a powdery material is used, a porous layer is formed on the surface of the mold, and then gradually melts with the cycle process, and then a homogeneous layer of uniform thickness is formed; if a liquid material is used, it flows and flows first.

Coated on the surface of the mold, when the gel point is reached, the flow stops completely. The mold is then transferred to the cooling work area, cooled by forced ventilation or water spray, and then placed in the work area, where the mold is opened, the finished part is taken away, and then the next cycle.